I assume you are talking about the balance transfer that the card is famous for. It is useful in the case if you want to transfer the balance on a different credit card to the Slate.
You likely will have a period of zero interest that would useful if you are paying interest on another card. Your chase statement for the card will tell you what your interest terms are.
Transferring funds to your checking will likely considered a cash advance meaning you get destroyed by the ~25% APR.
In summary the card is to help you pay down credit card balances faster if you are swimming in it.